[TowerTalk] Does prevailing grounding scheme promote large ground loop

[Dick Blumenstein]

Steve-

May the force be with you... (or should I say, it appears the force is 
with you TOO MUCH!).

(Sigh... when man makes plans, G-d laughs.)

Sorry for all your troubles.

I have no idea what I'll be facing here in the western foothills of NC. 
I'll find out, though; I'm sure.

PS - If you move to Oregon, then all your connections and equipment 
might corrode/rust!

Dick, K0CAT

======================


Steve London wrote on 7/26/2016 9:37 AM:
> K9YC wrote:
>
>> The problem with this (and any) analysis of a lightning event is that 
>> it is FAR more >complicated than anything we can compute, simply 
>> because the voltages and currents induced >in any system (stuff wired 
>> together) will be different in each conductor depending on >WHERE the 
>> strike is, the physical geometry of the conductors that make up that 
>> system, how >energy from the strike gets to the earth, etc.
>
> I can attest to that ! In 13 years of living on a dry, New Mexico 
> hilltop, I have learned a lot about mitigating lightning damage. 
> Frankly, the cost and effort of doing lightning protection "perfectly 
> right" is prohibitive. The approach I have settled on is simple 
> disconnection to keep the bulk of the lightning energy out of the 
> house. All RF and control cables to/from the towers (I have 3 towers, 
> with 5 rotator controls and a number of remote antenna switches) 
> terminate on a bulkhead panel about 30 feet from the house. During 
> lightning season (May-October), everything is disconnected at the 
> panel, except when I am on-the-air. All AC power to the ham shack is 
> disconnected, except when I am on-the-air (unplugged - I don't trust 
> the small air gap in switches and relays). Yes, this makes it 
> inconvenient to be on-the-air during the summer. Even with these 
> measures, I have learned the hard way about interconnectedness (K9YC's 
> "stuff wired together"). A nearby or direct hit to a tower will 
> destroy USB ports on computers and radios, if they are interconnected 
> with a USB cable. I have tried commercial USB optoisolators, but have 
> found they generate too much RF noise. The latest incident was earlier 
> this week. I had a direct hit. The only "stuff wired together" was an 
> Astron power supply, connected to a 2 meter radio. Just before the 
> storm, these were working fine. I unplugged the antenna from the 2 
> meter radio, and the AC power from the power supply. There was still a 
> 3' long power cable connecting the power supply and 2 meter radio. 
> After the storm, the power supply blew fuses. The root cause was a 
> fried LM723 in the power supply, causing the voltage to go high, and 
> the crowbar protection to be activated.
>
> Sometimes I think moving to relatively lightning-free coastal Oregon 
> would be a good idea !
>
> 73,
> Steve, N2IC
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>